Apparatus for effecting magnetically a separation between magnetizable and nonmagnetizable particles contained in liquids, slurries, and the like



P 1952 R. SYMINGTON El'AL 2,612,262

APPARATUS FOR EFFECTING MAGNETICALLY A SEPARATION BETWEEN MAGNETISABLE AND NONMAGNETISABLE PARTICLES CONTAINED IN LIQUIDS, SLURRIES, AND THE LIKE Filed March 27, 1951 2 SHEETSSHEET l azzrewce #6 4 By I I Attorney pt.. 1952 R. SYMINGTVON ET AL 2,612,262

APPARATUS FOR EFFECTING MAGNETICALLY A SEPARATION BETWEEN MAGNETISABLE AND NONMAGNETISABLE PARTICLES CONTAINED IN LIQUIDS, SLURRIES, AND THE LIKE- Filed March 2'7 1951 2 SHEETS-SHEET 2 F/GZ.

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Patented Sept. 30, 1952 a I ff; Y aBr itis h company toSimon-Carves, Lim

sLUnR1 s,f ND THE LIKE 1 Robert Symington and Laurence Hutcheson Oleat, Cheadle Heath, Stockport, England, assignors -fited, Stockport, England I ApplicationMai-chm, 1951', Serial NoL 217,713

In' Great Britain April 4, 1950 r KHS Claims. (01f. ate -5)] "g This invention relates' to apparatus f or effecting magnetically a. separation between magnetisable and non-magnetisable particlescontained in liquids-slurries and the like.

The apparatus forming the subject of this invention isparticularly suitable for, but is not confined to the separation and recovery of 'magnetise ableparticles from slimes and sands contained in spray waterand-thelikein coal preparation and oredressingprocessesworking on the float-andsink principle,=='where comminuted 'magnetisable material is used as a suspending medium Inthe sink-and-float process, a proportion of the." suspending medium: togetherwithslimes, sands,- and the like adhere'to the products of separation-leaving'the separating bath; and in order to minimise the loss of suspending medium itis customary to spray the products of separation withwater and to recover the; suspending medium from the spray water. V 1 v a .Whercthe suspending medium consists of finely divided magnetisable particles,-recovery thereof can be eifected magnetically by bringing the spray water or slurry containing the slimes, sands and magnetisable particles, into themagneticfield of amagnet arranged over a settling tank, so that the 'magnetisable particles are magnetised and consequently gagglomerate, the larger masses forme'd'by agglomeration, settling rapidly in the s'ettling' tankbyireason of their increased weight as compared with that of non-agglomerated par-' ticles. 'r' I I v "In" practice it is found that in order fully to magnetise the magnetisable particles so as to obtain maximum agglomeration and the highest rate of settling, it is necessary to arrange the polepiece of the magnet close to the surface of the waster in the settling tank, Withthe result that the magnetisableparticles are drawn magnetically on to the pole face of the magnet. j 1 e 1 i The magnetic action of the magneti's thus seriously reduced, and where a multiple-pole magnet is used, is practically nullified, since .the'polepieces of the magnet are'short-circuitedby the particles adhering to and bridging the pole-pieces, so providinga direct magnetic pathfor the magnetic'flux;

The magnetisable particles contained in'the slurry or 'Water" which thereafter flows to the settling 'tank, therefore become only :partially magnetise'd or are not magnetised at all; and efficient agglomeration and settling of the particles does-nottherefore take place.

:'..'I'he capacity-cf thisknown magnetic s"parator i's' thusmateriallyreduced. v I i j The principal object of thepresentinvention is to-provide a magnetic separating device'thecae pacity of which is made relatively high; by com centrating, thefield of infiuenceof the magnet into a small area and enabling, the l o cal-;-fi eld strength to.be concentrated withoutrisl; Oil-ga t: tracted magnetic; particles short-circuitingor bridging the, polevfa'ces I of the magnet,,.thereby ensuring that all themagnetic particles are ,rapidly magnetised to the fullest extent fi re+ after, as a result of agglomeration, settle at;-the maximum possible rate, 1; i 1 Y 3' Inthe magnetic separating apparatus accord;- ing to the present inventiomia settling tank-to which the liquid or 'slurryyto besubjected to the separating process is? fed, is provided 4 at;;,the:; t cp with a magnet which is adapted; to-produce .a highly concentrated localisedmagnetic fieldin the close vicinity of; or even below the levelifi ltained: by the liquid or slurry-entering the tanlg, and a travelling collector of non-magnetic mate,- rial is arranged tctravel un depthe ,polepfaces of the ma net, through the n'iag-nietic.field;1,so- -v that magnetisable particles contained in the. liquid or slurry and drawn magneticallyinto-the magnetic field, are intercepted-by; vthe collector whichis adapted to carry them intheir consequent mag netised and agglomerated;condition-out of; the

magnetic'field andinto a position in-the iiqui in theysettling, tank where they are freeto leave the collector and settle in the. settling'tank. z, r U

The settling tank hasa bQttomoutlet-forsettled magnetised and agglomeratedparticles, and; an outlet at; the top for; liquidcontainingnon-mags netisable particles, .the upper:outletbeing prefer,- ably formed-,by-arranging-the u per: rim of the tanlc; as; a-fiweir at a. level slightly lower than or correspondingapproximately with the desired-liq;- uid level-in thetankadjacent tothe magnet which together with the collector and the liquid inlet are preferably surrounded 'by.:a; -wal1 crpartition;- of non-magnetic material having its-lower ed e. Sub;- mergedin the liquid; so that the liquid containing the nonr-magnetisable ;particles is compelled to pass under that edge before escaping over the rim or weirofth'etank. 1 "21 'r- The slurry. is preferably fed into the tank by: pipe having a conical or like diverging nozzle-er;- ranged closelto the undersideof the collector be low the magnet. gAn' inlet pipe for clean-1 water may becprovidedtnearthe bottom of the tanlg-to inject a slow upward stream "of'clean water in "order to; guard? against settlement of large particles of non-magneticgslimesand sands.- :An example of magnetic separating and .densi- 3 fying apparatus according to the invention is il ustrated by theaccoinpan ing-drawings-wheres- 1n-- Figure 1 is a front sectional elevation of the apparatus on II Figure 2 and Figure 2 is a plan; Figure 3 is a sectional elevation air-part1 9. 3 h intercepting disc or collectopon alarger scale,.,

In the example illustrated" by; these drawin central annular wall 2 is such that itslowerend.

is submergedin the liquid or slurry.v

The slurry, consisting of finely-divided magnetisable and non-magnetisable particles in suspension in a liquid such as water is fed to the cone 'ljbynieans oi a feedpipe 6, which enters the wall of the cone about mid-way-thereof and is extended upwards within the cone. I The'upper end of'the feed pipe isprovidedwith aacenical, pyramidal" 01' like divergent nozzle '1, which is-adjustable in anup and down direction on theupperend of the feed pipe 6. so thatthe wider-end of the nozzle], whichforms-the outlet can be-set slightlybelow-thelevel attained by the liquid which has entered thecone and is indicated by the broken 'lineB; 8. The nozzle 1- may. be adjusted on the pipe 6, for example, by packing the connecting flanges .9, It or the flange I maybe screwed on the end of the pipe.

lhe nozzle! is made :of non-magnetic material and is arranged eccentrically within, the central annularwall 2.-

V electromagnet- II is supported directly "above the surfaceor'the liquid contained in the none I andydirectly-above the-nozzle T of the feed :RIWSQ Theelectromagnet H is advantageously multi apolar-sothat a highly concentrated local mag-- netic-fleld is created between the pole faces, in the close vicinity-of or-below the level 8-8 of the "liquidcontained in the cone, directly above the I "nozzle- 'l orthe feed pipe 6.

' The magnetic-field createdby the magnet I I is madeof'suchstrengththatin the absenceof interce'pting means, magnetisable particles would be withdrawn from the-slurry-by magnetic-action, err-to thepole i aces of the-maget. v "-Intercepti-ng meansare, however, provided, in form-of-a spinner-disc [3, arranged between 'the pole faces of'the magnet II and the top of "the nozzle 1 at the top of the-feed pipe 6. The spinner-disc I3 isarranged horizontally and is-maunted-on a spindle I4 to rotate slowly about-a vertical axis, concentric with the annular fwalM.

It is made of non-magneticmetal such as that known as nconelff Itis provided onits underside with: aseries ot radial-vanes l5, and-with a circumferential rim or-wall I 6.

The spinner disc I3 is rotatedslowly-'bysuitable means'withthe rim 1 6 just below =the level of the liquid in the cone, the upper surface. of the disc "being justabove the leveloi' the-liquid.

convenient means for-rotatingthe-disc com.- prises an electric motor I"! driving the spindle I4 through reduction gearing I8.

' A castor roller 25-carriedbya bracket "2 6. fixed to a beam-4 bears on'the upper surface of the disc. The beam- 4' forms of the generalsupporting framework 5 01 the apparatus, only aportion heinashown, 7

The beam 4 supportsa sub-trams II; on which the electric motor l1, gearing I8 and spindle I 4 are mounted.

The cone I is surrounded by a launder I 9 to receiye the liquid andnon-magnetisable particles escaping over thetpp edge or weir 20 the height .offwhich, determines the liquid level 88.

The; launder; l9 has a discharge pipe 2|.

The bottom of the cone I is provided with a discharge pipe22 whichmay be fitted with a valve ggl'preiera'bly "one capable of remote control such asa known type of pneumatically operated valve.

In operation, the slurry fed into the cone I 'throughgthexfeedpipe 6 and nozzle I comes under th ,mfipence of the highly concentratedand localisedmagnetic field of the magnet I I.

The magnetisable particles contained in the liquid are immediately-drawn magnetically into theifield' and: onto the. spinner disc I:3"whic h acts as acollector, such particles becoming fully mag. netised', and bymutual :magnetic attraction; therefore agglomerated. The. nonmagnetisable particles areentirely'unafiected.

The magnetised particles now held magnetically on the undersideof the spinner disc I3'by-the magnetic action of the field, are trapped between the radial vanes [5 of the disc, which preventsuch particles slipping on the. disc. and, remaining under the pole facesof'the magnet il I; as the .disc

rotates. I

As the spinner disc [.3 slowly rotates 171187.131 g-lomerated magnetised particlesare carriedby the disc out-of the magnetic field, and accordingly drop-rapidly from the dlscand' sinktothebottcm ofthe cone l. 7

The magnetised agglomerated particles-sink rapidly in the liquid containedin thecone I, and are subjected to the densiiying action of the cone, thereby concentrating"themselves in the bottom ofthe cone whence theycan be drawn oiT as a magnetic concentrate. through the pipe 22 asrea quired;

The non-magnetisable particles which"have a much lowersettling rate flow with the water under-the central annular wall .2' and" .over the top edge or weir 20 of the cone l' intothe launder I9 from which theyca-nbe dischargedthrough the discharge pipe 2 I as slimeelad'en water free from magnetisable particles.

The central annular wall 2 serves to divide the surface of the liquid-lathe cone I 'intogtwo areas.

Within the annular wall 2 .considerablexturhuilence may occur, whereas in the annulus. surrounding the central wall, the liquid" will..;be relatively quiescent.

The central annular wall 2 is made ofznonqmagnetic material, and it will be appreciated that the feed pipe v6', the magnet..ll, .,and;the spinner disc I3; are, located within the central annular wall 2.

Aslow upward stream of clean water"-may--.:be injected into the-cone I at or-near the bottom thereof for instancev by a pipe 24' inv order; to guard against the settlement of large. particles iOf non-magnetic slimes and sands, therebyfleftesting a sharper separation between the 11011:- magnetic materialwhich is .to flow over thetop edge.- or weir 2.0 of. the -.cone.; l5, :from the magnetised agglomerates which are. to. bendischarged from the bottom of the cone:.-through;the :pipe: 122.,

"The liquid or-slurry ied; by the-pipe ,6; to. the cone I may be spray watergfrom-a..cualz'washin or ore dressing plant operating on the sink-andfioat principle, utilising finely divided magnetisable material as the suspending medium.

It will be understood that the inlet pipe 6 may be provided with means for regulating the rate of I fiow of the slurry fed by it to the cone so as to guard against undue turbulence in the vicinity of the magnetic field and collector at the top of the cone, and also undue rate of flow under'the annular wall 2, so as to allow the collector to operate efliciently and to ensure settlement in the tank I of the separated magnetic particles discharged from the collector.

The rate of fiow will naturally vary according to the nature of the particles to be separated.

Similarly the clean water inlet pipe 24 when used may be provided with means for regulating the rate of flow of injected water.

We claim:

1. An apparatus forveffecting magnetically a separation between magnetisable and non-mag netisable particles contained in liquid, slurry or the like comprising a settling tank, means for feeding liquid, slurry or the like to said tank, a magnet at the top of the tank for producing a highly concentrated localised magnetic field in the vicinity of the level of liquid in the tank, a collector disc of non-magnetic material mounted adjacent to the magnet and means for rotating said collector discv under the pole faces of the magnet for the purpose of intercepting magnetic particles contained in the liquid and attracted into the magnetic field and for carrying said collected particles into a, position in the liquid out of said magnetic field for release and'settlement in the tank, said means for feeding slurry into the tank comprising a pipe having a divergent outlet nozzle situated close to the underside of said collector disc and below said magnet for the purpose of feeding the slurry immediately into the magnetic field produced by said magnet.

2. An apparatus for effecting magnetically a separation between magnetisable and non-magnetisable particles contained in liquid, slurry or the like as specified in claim 1 wherein said'collector disc is provided with radial vanes on its underside and a circumferential rim having its lower edge immersed in the liquid in the tank.

3. An apparatus for effecting magnetically a separation between magnetisable and non-magnetisable particles contained in liquid, slurry or the likecomprising a settling tank having an outlet for the discharge of densified magnetisable particles at the bottom of said tank, and an overflow outlet at the top of said tank for the discharge of liquid containing non-magnetisable particles, means for feeding slurry into said tank,

a partition at the top of the tank partly submerged in the liquid in the tank and enclosing an area of said liquid, a magnet mounted at the .magnetic particles contained in the liquid and liery Engineering, December 506.

- attracted into the magnetic field, and for carryi 1 the purpose of delivering the slurry immediately into the magnetic field produced by said magnet.

4. An apparatus for effecting magnetically a separation between magnetisable and non-magnetisable particles contained in liquid, slurry or the like, comprising a conical settling tank having an overflow weir at its top for discharge of liquid containing non-magnetisable particles, an outlet at its bottom for densified magnetisable particles, an annular partition partly submerged in the liquid at the top of the tank and in spaced relation to said overflow weir, a feed pipe pro-- vided with a divergent nozzle extending into the liquid enclosed by said partition, a magnet mounted at the top of said tank close above said nozzle for producing a highly concentrated localised magnetic field in the vicinity of the level of the liquid which has entered the tank from said nozzle, a collector disc of non-magnetic material mounted adjacent to said magnet and means for rotating said collector disc below the pole faces of said magnet for the purpose of intercepting magnetisable particles in the liquid attracted into the magnetic field and for carrying them into a position out of said field but within the area of liquid enclosed by said partition for release and settlement in the tank.

5. An apparatus for effecting magnetically a separation between magnetisable and non-magnetisable particles contained in liquid, slurry or the like, as specified in claim 4 wherein the settling tank is provided with an inlet pipe near its bottom for injecting clean water for the purpose of assisting the separation of non-magnetisable particles which are to flow over the weir from the magnetised agglomerates which are to be discharged from the bottom of the tank.

ROBERT SYMINGTON. LAURENCE HUTCHESON CLEAT.-

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS I Date OTHER REFERENCES Simon-Carves Dense-Medium Washer, 001- 1951, pages 501 to 

